AA 4689 then DL 543 at Atlanta
Washington National → Atlanta → St Louis
Timetable, Atlanta time
19:44AA 4689 from Washington National at the gate
15:45DL 543 to St Louis leaves the gate
20 h 01 apart on the timetable, overnight
DL 543 leaves 20 h 01 after AA 4689 arrives on the timetable: more than half a day, so not a connection we count.